Volcanic sulfur dioxide and acute respiratory symptoms on Miyakejima island

• Published in: Occupational and environmental medicine (London, England) Vol. 65; no. 10; pp. 701 - 707
• Main Authors: Ishigami, A, Kikuchi, Y, Iwasawa, S, Nishiwaki, Y, Takebayashi, T, Tanaka, S, Omae, K
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.10.2008; BMJ Publishing Group; BMJ; BMJ Publishing Group LTD
• Subjects: Acute Disease; Adolescent; Adult; Aged; Air; Air Pollutants - analysis; Air Pollutants - toxicity; Asthma; Biological and medical sciences; Cough; Diseases; Dose response relationship; Environmental Exposure - adverse effects; Environmental Exposure - analysis; Environmental pollutants toxicology; Eye irritation; Female; Gases; Guidelines as Topic; Health care; Health risk assessment; Health risks; Humans; Incidence; Japan - epidemiology; Lung diseases; Male; Medical sciences; Medical screening; Middle Aged; Outdoor activities; Outdoor air quality; Personal protective equipment; Pharyngitis; Respiratory diseases; Respiratory symptoms; Respiratory Tract Diseases - chemically induced; Respiratory Tract Diseases - epidemiology; Sulfur; Sulfur dioxide; Sulfur Dioxide - analysis; Sulfur Dioxide - toxicity; Throat; Toxicology; Volcanic eruptions; Volcanic Eruptions - adverse effects; Volunteerism; Young Adult; Asia; Japan; Human; Natural origin pollution; Toxic gas; Volcanic eruption; Respiratory disease; Acute; Sex; 2000; Epidemiology; Island; Sulfur dioxide; Symptomatology; Irritant compound; Air pollution; Woman; Public health
• ISSN: 1351-0711; 1470-7926
• DOI: 10.1136/oem.2007.033456

Objectives: Following a volcanic eruption in 2000, high concentrations of ambient sulfur dioxide (SO2) are still observed on Miyakejima, Japan despite the reversal 2 years ago of the ban on residents living on the island. This study examines the association between current levels of volcanic SO2 and the incidence of acute subjective symptoms in volunteers on Miyakejima. Methods: The authors conducted a follow-up study on 611 healthy volunteers, on a person-hour basis (28 413 person-hours), who visited the island to provide support to residents from February to July 2005. Adverse health symptoms were measured by self-administered diary and exposure was approximated using monitoring data across 14 sites. Associations between incidence rates and increasing SO2 levels (reference (the lowest), very low, low, middle and high) were examined using Poisson regression. Results: Hourly incidence of cough, scratchy throat, sore throat and breathlessness showed clear exposure–response relationships with SO2 concentrations. There were statistically significant risks of those symptoms at relatively low SO2 levels. Thus, rate ratios in the 0.6-2.0 ppm exposure band (vs <0.01 ppm) were: for cough, 3.4 (95% CI 1.8 to 6.6) in men and 9.8 (3.9 to 24.9) in women; for sore throat, 3.2 (1.7 to 6.2) in men and 5.8 (2.0 to 16.5) in women; and for breathlessness, 10.5 (4.2 to 26.6) in men and 18.5 (4.6 to 74.3) in women. Little evidence of SO2 effects on sputum and nasal discharge/congestion was observed in this study. Eye and skin irritations showed inconsistent results between hourly maximal and hourly mean SO2 concentrations. Conclusion: The authors observed strong evidence of an exposure–response relationship between volcanic SO2 and subjective acute respiratory symptoms among a healthy population on Miyakejima. The results are consistent with reports that females and non-smokers are more sensitive to irritant gas than males and smokers, respectively.